Need help identifying a NPT fitting.

[Cerby86]

Okay so I've searched through the net and I'm still totally confused about how to find what size this fitting is so I can order a replacement!!
Fucking americans can't even name a pipe fitting sensibly and then you have to take into account their retarded measurement system based on how far an average horse can pull an average penis using a standard length of chain while burning incense and chanting to the great gods of we aren't changing to the same system as EVERYONE ELSE cos we are the centre of the god damn universe etc etc.
God I hate the imperial system hahaha.

Anyway so the fitting is a npt fitting with a push on barb used in a surge tank setup.
The main measurements of the fitting are 20mm OD of the thread 21mm width on the hex part, 12mm OD on the barb. 13.5mm ID on the threaded end, 8.5mm ID on the barb end.
Keep in mind these measurements ar all "ish" cos the plastic micrometer I have is shit.

Anyway if anyone understands how to work out the measurements then your are the master of a dark art and I will be forever grateful!
Cheers
Mark

[takai]

IF it is NPT, then 20mm on the thread outer (i assume not the root) is 1/2NPT.

[Cerby86]

yeap its outer diameter (OD) and its definitely tapered and I don't we are using old british stuff here in aus so I assumed it was npt.
See the thing that confuses me is that I have some 3/8 fittings and they are like half the diameter!

[takai]

Its because the NPT standard refers roughly to the ID of the pipe, not the OD of the fitting.

Similar to AN standard, where the number is the ratio of the ID of the hose its attached to.

[Cerby86]

ah okay, I suppose there is some form of logic to that. It would be so much easier if they just stamped the size on every fitting lol

[toygt]

be carefull the difference between npt and bspt is 1 thread per inch so they kinda fit

[Sam-Q]

toygt is right, it's a good idea to have a thread gauge for metric and the barbaric.